1. Field of the Invention
The present invention relates to a technology for cleaning toner from an image carrier in an image forming apparatus.
2. Description of the Related Art
In image forming apparatuses such as a photocopier, a facsimile, and a printer, noise can be caused when a cleaning blade, which cleans a surface of an image carrier, or a driving motor, which generates driving force to drive the image carrier and the like, deteriorates. Such a cleaning blade and a driving motor that have deteriorated should be replaced with new ones. This is because there is a high possibility that a normal operation becomes impossible with those parts and if the apparatus is kept being used without changing those parts, the image carrier or members in a driving transmission system can be damaged. The high-pitched large noise generated from a deteriorated cleaning blade is called blade noise.
Meanwhile, in Japanese Patent Application Laid-open No. 2004-226482, an image forming apparatus has been proposed that detects an abnormal part based on a result obtained by collecting sound generated inside the apparatus with a microphone as a sound sensor and that informs of an abnormal part in the apparatus. Specifically, the image forming apparatus analyzes intensity of each of sound components having certain frequencies f1, f2, f3, and f4 different from each other among sound components having frequencies different from each other included in sound obtained by the microphone. When the intensity of the sound component having frequency f1 exceeds a preset value, the apparatus assumes that a first motor that generates sound having frequency f1 during the operation is in an abnormal state, and displays a message to inform the same. Similarly, when the intensity of the sound components of frequencies f2 and f3 exceeds the preset value, the apparatus assumes that a second motor and a third motor are in an abnormal state, and displays a message informing the same. Moreover, when the intensity of the sound component having frequency f4 that is generated by friction between a photoconductor serving as the image carrier and a cleaning blade exceeds the preset value, the apparatus assumes that the blade noise is caused, and displays a message informing the same. Such a configuration enables to urge a user to replace those parts by informing an abnormal state when the blade noise occurs or various kinds of motors are in an abnormal state.
However, in the image forming apparatus, cleaning failure cannot be accurately detected as an abnormal state caused by deterioration of the cleaning blade. Specifically, the main cause of the blade noise is excessive friction between the blade and the photoconductor due to increased abutting area of the blade with the photoconductor caused by seriously worn edge of the cleaning blade. As friction excessively increases, relatively large high-pitched rubbing noise is generated. On the other hand, cleaning failure occurs when toner on the image carrier escapes through the abutting part between the image carrier and the blade in a state where the blade and the image carrier are in poor contact because of partial wear or deterioration of the blade. Because this is caused by partial poor contact between the blade and the image carrier, it is often the case that the blade noise is not generated. Furthermore, even if the blade noise occurs, it does not necessarily mean cleaning failure is caused. Therefore, the image forming apparatus described in Japanese Patent Application Laid-open No. 2004-226482 cannot detect cleaning failure accurately.